Field
Aspects of the present invention generally relate to an image forming apparatus having a sensor for detecting an object such as a person.
Description of the Related Art
Techniques for returning from a power-saving state when an image forming apparatus detects an object such as a person with a sensor provided in the image forming apparatus are known (see Japanese Patent Application Laid-Open No. 2012-118253). The image forming apparatus discussed in Japanese Patent Application Laid-Open No. 2012-118253 includes a sensor for detecting a moving object existing within a predetermined range around the image forming apparatus. When the sensor detects the moving object, the image forming apparatus shifts from a power-saving state to a standby state in which the power consumption amount is larger than that in the power-saving state.
The image forming apparatus discussed in Japanese Patent Application Laid-Open No. 2012-118253 includes, in addition to the above-described sensor, a power-saving button for shifting the power state in the image forming apparatus from the power-saving state to the standby state. In response to a pressing operation of the power-saving button by a user, the image forming apparatus shifts from the power-saving state to the standby state.
In some cases, the power-saving button has also a function, in addition to the function for shifting the power state in an image forming apparatus to return from the power-saving state to the standby state, for shifting the power state in the image forming apparatus from the standby state to the power-saving state (see Japanese Patent Application Laid-Open No. 2012-248961). In a state where a value of a power mode register indicating a power state in an image forming apparatus is “001” (indicating that the image forming apparatus is in a power-saving state), if the power-saving button is pressed, the image forming apparatus shifts the power state in the image forming apparatus from the power-saving state to the standby state. In a state where a value of the power mode register indicating a power state in the image forming apparatus is “010” (indicating that the image forming apparatus is in the standby state), if the power-saving button is pressed, the image forming apparatus shifts the power state in the image forming apparatus from the standby state to the power-saving state.
In such an image forming apparatus that shifts from the power-saving state to the standby state in response to the detection of an object such as a person by the sensor, after the detection of the object such as a person by the sensor, the image forming apparatus takes a predetermined period of time to return from the power-saving state to the standby state. This is because the device to which the power supply has started needs a predetermined time for the boot processing. Due to the booting operation, when the user arrives in front of the image forming apparatus, in some cases, the image forming apparatus has not returned to the standby state. In such a case, the user who has arrived in front of the image forming apparatus may mistakenly think that the image forming apparatus has not returned to the standby state, and press the power-saving button to instruct the image forming apparatus to return from the power-saving state to the standby state.
However, if the power-saving button is pressed while the image forming apparatus is shifting from the power-saving state to the standby state in response to the detection of the object by the sensor, the image forming apparatus determines that the pressing operation of the power-saving button is an instruction for shifting from the standby state to the power-saving state. This is because, at the time the object such as a person is detected by the sensor, the value of the power mode register in the image forming apparatus becomes to “010”, and when the value of the register is “010”, the power-saving button is pressed. As a result, after the shift from the power-saving state to the standby state, the image forming apparatus immediately shifts to the power-saving state.